Numbers

GNU Emacs supports two numeric data types: integers and floating-point numbers. Integers are whole numbers such as -3, 0, 7, 13, and 511. Floating-point numbers are numbers with fractional parts, such as -4.5, 0.0, and 2.71828. They can also be expressed in exponential notation: ‘1.5e2’ is the same as ‘150.0’; here, ‘e2’ stands for ten to the second power, and that is multiplied by 1.5. Integer computations are exact. Floating-point computations often involve rounding errors, as the numbers have a fixed amount of precision.

• Integer Basics		Representation and range of integers.
• Float Basics		Representation and range of floating point.
• Predicates on Numbers		Testing for numbers.
• Comparison of Numbers		Equality and inequality predicates.
• Numeric Conversions		Converting float to integer and vice versa.
• Arithmetic Operations		How to add, subtract, multiply and divide.
• Rounding Operations		Explicitly rounding floating-point numbers.
• Bitwise Operations		Logical and, or, not, shifting.
• Math Functions		Trig, exponential and logarithmic functions.
• Random Numbers		Obtaining random integers, predictable or not.